PRNP polymorphisms in Greek goats affected with natural scrapie.

Evridiki Boukouvala, Efstathios Katharopoulos, Paula Stewart, Vayia Palaska, Nektarios Giadinis, Georgios Arsenos, Loukia Ekateriniadou, Wilfred Goldmann, Jan Langeveld

Research output: Contribution to journalMeeting abstract

Abstract / Description of output

Introduction. As a part of an EU EMIDA ERA-NET project entitled “Towards breeding of goats for genetically determined TSE resistance” we analyzed 295 brain tissue samples from scrapie affected Greek goats for PRNP gene variability and disease association.
Material and Methods. In total, 295 brain tissue samples from naturally affected goats were analyzed from 71 herds. qPCR was used for genotyping the PRNP coding region positions 110, 146, 211 and 222 and in a selected number of animals direct sequencing was carried out for verification of polymorphisms and for the PRNP gene promoter region analysis. The SPRN gene encoding Shadoo protein was partly sequenced for animals with genotype 222QK.
Results. All goats were PRNP genotypes 110TT and 146NN equivalent to wildtype PrP. In contrast, the polymorphism R211Q was detected in 11 animals (3.7%) from 4 herds. Surprisingly, the polymorphism Q222K was detected in 13 samples (4.4%) from 5 herds with a total population of 1138 animals. Negative controls were not collected at the time, but our analysis of 25 healthy herds with over 800 animals resulted in an average K222 carrier frequency of 7.5% (range 3-16%). Based on this data, we estimate that the frequency of scrapie cases amongst K222 carriers is 7-15% in these five herds. We reasoned that the unexpectedly high occurrence of the K222 variant in scrapie-affected goats could be linked to an unusual PRNP promoter haplotype linked to different expression control; this was not supported by our sequence analysis. A polymorphism in the SPRN gene previously associated with scrapie susceptibility in Italian goats was found in 33% of the 222QK affected goats.
Conclusions. The absence of either 146S/D polymorphisms in scrapie positive Greek goats supports the hypothesis that they are associated with resistance. The observation of scrapie-positive K222 carriers in 4 different geographical areas and in 5 out of 71 infected flocks was surprising based on previous studies that had shown strong association of K222 with resistance.1 Our study appears to indicate a much higher incidence of scrapie in 222K carriers than reported for French goats. There was no evidence from the PRNP gene sequences that the K222 allele in these Greek goats contains additional mutations associated with susceptibility nor that there is a particular SPRN allele in these goats. This leaves us to propose that either especially strong infection pressure in these herds or a different scrapie strain may be responsible for these cases. Investigations to test this are currently performed. 1Corbiere et al., 2013, J Gen Virol 94.
Original languageEnglish
Article numberP.87
Pages (from-to)65
Number of pages1
Issue numberSupplement
Publication statusPublished - May 2014


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